Law enforcement officials at Huntsville Maximum Security Prison in Texas on Thursday (local time) executed the oldest of the state's approximately 200 death row inmates.
Carl Buntion, 78, was sentenced to death for the 1990 traffic stop murder of police officer James Irby.
Buntion said on Houston television station KHOU last week that he regrets his actions every day.
This statement surprised her, explained the police officer's widow, Maura Irby, in KHOU.
Buntion has never shown remorse.
After the execution, Irby told media that she still misses her husband to this day.
Catholic nun and anti-death penalty activist Helen Prejean questioned the public safety of the execution of an old man with multiple chronic illnesses.
According to the Texas Tribune, Buntion was officially pronounced dead 13 minutes after being administered the drug pentobarbital.
According to the Texas Coalition Against the Death Penalty, Buntion was transported to a hospital last week for an evaluation of chest pains.
The emergency room found pneumonia.
In Tennessee, Gov. Bill Lee on Thursday delayed the execution of 72-year-old Oscar Smith about an hour before the execution date.
An error was noticed in the preparation of the lethal injection.
According to the death sentence, Smith murdered his estranged wife and their two sons in 1989.
His defense has protested that new DNA tests indicated innocence.